1. Field of the Invention
The present invention relates to the creation of a spatial separation between individual, closely-spaced products moving on a high-speed conveyor and particularly to the interception and acceleration of such products followed immediately by the deceleration of the products in order to ensure against the impact thereof against a fixed stop at a downstream distribution point with sufficient force to cause damage to the products. More specifically, this invention is directed to apparatus for transferring books, book blocks, newspapers, stacks of folded or unfolded sheets of printed matter and other similar products from a high-speed conveyor to a distribution point and especially to transfer apparatus which creates a space between serially received incoming products while at the same time ensuring that the motion of the products is controllably retarded in the interest of gentle treatment. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Prior Art
While not limited thereto in its utility, the present invention is particularly well suited for use in association with a book binding machine. Finished or partially finished products discharged from a book binding machine, such as books, inner books, newspapers, stacks of sheets, or the like, are typically stacked for further processing. These products are customarily of rectangular shape and will serially exit the book-binding machine positioned in close proximity to one another on a high-speed conveyor. The conveyor delivers the products to a distribution point where vertical stacking in a hopper or on an elevator-type mechanism will be accomplished or where the products are otherwise individually handled and their direction of motion changed. In the case of vertical stacking, the desired vertical orientation is, in part, achieved through causing the in-coming products to contact a stop which arrests the motion thereof. Because of the speed at which the products move on the conveyor, particularly in the case of a book-binding machine which operates at a high production rate, it is in practice difficult to obtain the desired vertical alignment. Also, as a consequence of the momentum which the products acquire, damage may occur as a result of the impact against the stop.
Published German Patent Application 39 38 536 discloses apparatus for forming a stack of folded sheets, the folded sheets standing on edge. This prior art apparatus employs braking rollers disposed between a delivery conveyor and a table on which the sheets are stacked. The braking rollers of the apparatus shown in the published German application are driven at a relatively low rotational speed, i.e., at a speed which is less than that of the delivery conveyor, and thus transfer the in-coming folded sheets to the table at a reduced forward speed. In theory, the braking rollers prevent any rebound or jolting of the folded sheets. In order for the apparatus of the published German application to function properly, a relatively large space must be provided between the individual folded sheets which are serially ejected from the upstream folding machine. If a sufficiently large separation is not maintained, sheets moving on the delivery conveyor may run up onto adjacent, leading sheets and proper stacking will not occur, i.e., the apparatus of German Application 39 38 536 does not have the capability of creating a separation between folded sheets when such separation does not exist.